Method and apparatus for enhancing security mechanism in unicast mode sidelink communication in a wireless communication system

Abstract

A method and device for a second User Equipment (UE). In one embodiment, the second UE establishes a unicast link with a first UE. Furthermore, the second UE is not allowed to initiate a direct link identifier update procedure or a direct link modification procedure if at least the second UE is performing any direct link re-keying procedure triggered by the first UE for the unicast link.

The invention claimed is: 
     
       1. A method for a second User Equipment (UE), comprising:
 establishing a unicast link with a first UE; and 
 not allowing the second UE to initiate a direct link identifier update procedure or a direct link modification procedure when the second UE is performing a direct link re-keying procedure triggered by the first UE for the unicast link established between the first UE and the second UE. 
 
     
     
       2. The method of  claim 1 , wherein the second UE is not allowed to initiate the direct link identifier update procedure or the direct link modification procedure if at least a specific timer for the unicast link is running on the second UE. 
     
     
       3. The method of  claim 2 , wherein the specific timer for the unicast link is T5091. 
     
     
       4. The method of  claim 1 , wherein the second UE is aware of a need for initiating the direct link identifier update procedure or the direct link modification procedure with the first UE for the unicast link. 
     
     
       5. The method of  claim 4 , wherein the need for initiating the direct link identifier update procedure means the second UE changes application layer identifier (ID) or a privacy timer of the second UE's layer-2 ID expires. 
     
     
       6. The method of  claim 4 , wherein the need for initiating the direct link modification procedure means the second UE adds, modifies or removes at least one of a PC5 Quality of Service (QoS) flow and a Proximity-based services (ProSe)application/service for the unicast link. 
     
     
       7. The method of  claim 1 , wherein the direct link re-keying procedure is used for updating security context of the unicast link. 
     
     
       8. The method of  claim 1 , wherein the second UE is not allowed to initiate the direct link identifier update procedure or the direct link modification procedure means that the second UE is prohibited to initiate the direct link identifier update procedure or the direct link modification procedure. 
     
     
       9. A second User Equipment (UE), comprising:
 a control circuit; 
 a processor installed in the control circuit; and 
 a memory installed in the control circuit and operatively coupled to the processor; 
 wherein the processor is configured to execute a program code stored in the memory to:
 establish a unicast link with a first UE; and 
 not allow the second UE to initiate a direct link identifier update procedure or a direct link modification procedure when the second UE is performing a direct link re-keying procedure triggered by the first UE for the unicast link established between the first UE and the second UE. 
 
 
     
     
       10. The second UE of  claim 9 , wherein the second UE is not allowed to initiate the direct link identifier update procedure or the direct link modification procedure if at least a specific timer for the unicast link is running on the second UE. 
     
     
       11. The second UE of  claim 10 , wherein the specific timer for the unicast link is T5091. 
     
     
       12. The second UE of  claim 9 , wherein the second UE is aware of a need for initiating the direct link identifier update procedure or the direct link modification procedure with the first UE for the unicast link. 
     
     
       13. The second UE of  claim 12 , wherein the need for initiating the direct link identifier update procedure means the second UE changes application layer identifier (ID) or a privacy timer of the second UE's layer-2 ID expires. 
     
     
       14. The second UE of  claim 12 , wherein the need for initiating the direct link modification procedure means the second UE adds, modifies or removes at least one of a PC5 Quality of Service (QoS) flow and a Proximity-based services (ProSe)application/service for the unicast link. 
     
     
       15. The second UE of  claim 9 , wherein the direct link re-keying procedure is used for updating security context of the unicast link. 
     
     
       16. The second UE of  claim 9 , wherein the second UE is not allowed to initiate the direct link identifier update procedure or the direct link modification procedure means that the second UE is prohibited to initiate the direct link identifier update procedure or the direct link modification procedure. 
     
     
       17. A second User Equipment (UE), comprising:
 a control circuit; 
 a processor installed in the control circuit; and 
 a memory installed in the control circuit and operatively coupled to the processor; 
 wherein the processor is configured to execute a program code stored in the memory to:
 establish a unicast link with a first UE; 
 determine that the second UE is not allowed to initiate a direct link identifier update procedure or a direct link modification procedure when the second UE is performing a direct link re-keying procedure triggered by the first UE for the unicast link established between the first UE and the second UE; and 
 determine that the second UE is allowed to initiate the direct link identifier update procedure or the direct link modification procedure when the second UE is not performing a direct link re-keying procedure triggered by the first UE for the unicast link established between the first UE and the second UE. 
 
 
     
     
       18. The second UE of  claim 17 , wherein the second UE is not allowed to initiate the direct link identifier update procedure or the direct link modification procedure if at least a specific timer for the unicast link is running on the second UE. 
     
     
       19. The second UE of  claim 18 , wherein the specific timer for the unicast link is T5091. 
     
     
       20. The second UE of  claim 17 , wherein the second UE is aware of a need for initiating the direct link identifier update procedure or the direct link modification procedure with the first UE for the unicast link.